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Question Posted 07/07/20:
What refocusing flip train was used for the dual-echo FSE sequence by GE scanners in the ADNI-1 study? I cannot find the protocol sheet for GE scanners.
Response posted 07/28/20 by Matt Senjem:
I have asked our MR physicist and he said that he believes that in the ADNI-1 GE Axial PD/T2 FSE pulse sequence, refocusing flip angle was defaulted, and not a user input.
You should be able to find it in the DICOM header element (0018,1314). I hope this helps, please let us know if you still have questions.
Response posted 07/28/20 by Gitanjali:
Thank you for your reply.
(0018,1314) has a value of 90 degree. Isn't it too low for FSE?
As per GE's DICOM Conformance statement-(0018,1314) reports Primary excitation pulse spin tip angle with the exception: "Represents spin-echo refocusing pulse tip angle when (0019, 109E) equals FSE, (0018, 0023) equals 2D (2D Fast Spin Echo), AND
(0019, 10B5) (user data 14) equals 1."
I checked the header- (0019, 10B5) equals 0.
Is there any other dicom tag/ document that specifically states the value of the Refocusing pulse tip angle? (Just want to add that I am looking at ADNI-1, 3T data).
Response posted 07/29/20 by Matt Senjem:
Upon further inspection, the value you are searching for may be this one in GE private tag (0021,105b).

(0021, 105b) [Tagging Flip Angle] DS: "180.000000"

Response posted 07/29/20 by Gitanjali:
Thank you for your patience with my query.
I looked at the (0021,105b) in ten 3T GE subjects from ADNI-1 and only one of them has a value of 180 in (0021,105b). The value is set to '0' in all other 3T subjects.
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